Welcome to the club! No one is perfectly happy all the time.

Therefore many people just accept their level of happiness.

Interestingly human beings experience a feeling that protects them from stagnation. This feeling is boredom. Even if you think that you are happy and succesful enough the world does not stop. Your environment will constantly change.

That means that you have a choice. You either wait doing nothing, or you keep growing and evolving.